1. Field of the Invention
This invention relates to a part of a bicycle, and more particularly to a quick release device.
2. Description of the Related Art
Referring to FIG. 1, a conventional quick release device is mounted to a front fork 11 of a bicycle, and includes an axle tube 12, left and right pushing blocks 13, 13′, a driving unit 14, a rotary lever 15, and a movable shaft 16.
The axle tube 12 extends through the front fork 11, and includes a tube wall 122 disposed around and extending along an axis 121 and having two deformable sections 123 disposed respectively at two opposite ends of the tube wall 122. Each of the deformable sections 123 has a frustoconical inner wall surface 124, and a plurality of open-ended slots 125 parallel to the axis 121 and formed through the tube wall 122.
Each of the left and right pushing blocks 13, 13′ extends along the axis 121, is disposed within the corresponding deformable section 123, and has a pushing surface 131 for contact with the corresponding frustoconical surface 124.
The driving member 14 is cylindrical so as to serve as a rotating shaft, extends along a horizontal direction perpendicular to the axis 121, and is formed with a counterbore 140 in a middle portion thereof.
The rotary lever 15 is rotatable about the driving member 14, and has a pressing surface 151 and a release surface 152 that are opposite to each other. The distance between the pressing surface 151 and the driving member 14 is greater than that between the release surface 152 and the driving member 14.
The movable shaft 16 extends along the axis 121 and through the counterbore 140 in the driving member 14, the rotary lever 15, and the left and right pushing blocks 13, 13′. An enlarged right end of the movable shaft 16 abuts against the driving member 14. A left end of the movable shaft 16 is connected fixedly to the left pushing block 13.
The rotary lever 15 is pivotable relative to the axle tube 12 between a pressing position and a release position. When the rotary lever 15 is pivoted to the pressing position, the pressing surface 151 comes into contact with the right pushing block 13′, so that the movable shaft 16 pulls the left pushing block 13 to press the pushing surfaces 131 against the frustoconical surfaces 124 of the deformable sections 123. At this time, due to the presence of the open-ended slots 125, the deformable sections 123 expand to thereby press the axle tube 12 against the front fork 11. Hence, the axle tube 12 is secured to the front fork 11. It should be noted that, the axle tube 12 may be mounted to a rear dropout (not shown).
When the rotary lever 15 is pivoted to the release position, the release surface 152 comes into contact with the right pushing block 13′ to release the left and right pushing locks 13, so as to separate the pushing surfaces 131 from the frustoconical surfaces 124. Hence, the deformable sections 123 are returned to their original shapes, and can be separated easily from the front fork 11. At this time, the axle tube 12 can be removed from the front fork 11.
Since the open-ended slots 125 are formed in the deformable sections 123, the axle tube 12 can be pressed directly against and secured to the front fork 11. When used for a long time period, or when frequent assembly and disassembly occur, the front fork 11 and the axle tube 12 experience serious wear therebetween, thereby reducing the service life of the quick release device. Furthermore, to move the left and right pushing blocks 13, 13′ simultaneously, the movable shaft 16 needs to have a length proximate to the axle tube 12. This results in an increase in the manufacturing cost and total weight.